Aliphatic polyamides, particularly nylon 6 and nylon 6,6 are extensively used for a variety of industrial and consumer applications such as carpets and automotive parts. Recycling and recovery of polymer from these products is important for environmental reasons. Such recovered polyamide material need to be separated from foreign materials such as carpet backing, etc. While there are several approaches to reclamation by chemical means wherein waste nylon is broken down to low molecular weight polymer or monomers which can be purified and reused to make high quality polyamide, these routes are expensive. It would be desirable to isolate the polymer with little, if any, loss of molecular weight by some other techniques.
Aliphatic polymers, in general, are soluble in selected solvents and thus a solutioning process could offer a route to recycle/recover polymers. The solvents for nylon are polar, often reactive and need to be handled with extreme caution for safety reasons. From a processing point of view, solvents that dissolve polyamides at elevated temperatures at atmospheric pressure, and from which the polymer precipitates on cooling and can be isolated by filtration are preferred. Certain polyols and carboxylic acids are such solvents, however, they are reactive and contribute to degradation of molecular weight of the polyamide. While some loss in molecular weight can be tolerated, severe degradation makes the product unsuitable for extrusion purposes (e.g. fibers and films) and as a molding compound. The present invention is directed to alleviation of this problem.